An Atypical Case of IgG4 Nephropathy
- Glomerular Diseases: Clinical, Outcomes, Trials - I
November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1303 Glomerular Diseases: Clinical‚ Outcomes‚ and Trials
- Azuero, Andres Jose, Mount Sinai Medical Center, Miami Beach, Florida, United States
- Zambrano, Cesar, Mount Sinai Medical Center, Miami Beach, Florida, United States
- Velar, Alex A., Mount Sinai Medical Center, Miami Beach, Florida, United States
- Da Costa, Jonathan, Mount Sinai Medical Center, Miami Beach, Florida, United States
IgG4 disease is a rare fibroinflammatory condition that affects many organ systems. We present a case of isolated IgG4 Nephropathy in a patient with HIV.
A 61 yr old male with history of controlled HIV on HAART presented to the Nephrology clinic for 1 year of progressively worsening bilateral lower extremity edema. He had no other associated urinary, respiratory, cardiovascular or rheumatologic symptoms. Laboratory data was remarkable for: UA with 4+ protein, 10 to 30 WBC, 10 RBC and hyaline casts. Creatinine was 1.45mg/dl, BUN 20mg/dl, Albumin 2.4g/dl and a 24 hr urine protein excretion of 9gr. Kidney biopsy showed chronic active tubulointerstitial nephritis with many IgG4 staining plasma cells and eosinophils. Glomerular capillary wall staining for IgG, C3, Kappa and lambda was present with negative PLA2R immunostaining. Findings suggested IgG4-KD with mixed phenotype of both TIN and MGN. IgG4 levels, serologies for post-infectious, autoimmune and hematologic diseases were normal and there were no imaging findings of retroperitoneal fibrosis, renal masses, hepatitis/pancreatitis or neoplastic disease. The patient was treated with an ARB, a diuretic and 1 mg/kg of prednisone. He has had a good response to treatment without signs of relapse.
IgG4 disease with Isolated renal involvement has been described in a minority of case report series. There is uncertainty of whether this is a distinctive phenotypic hallmark or a time sensitive matter. Most cases are characterized by TIN and only about 7% present with MGN and nephrotic range proteinuria. Of those, half of the subjects had a mixed histology with both TIN and MGN as our patient did. TIN is presumed to be responsible for disease progression and fibrosis. Most cases have a favorable response to prednisone. Rituximab can be considered in case of severity or recurrence. Lack of robust data make it difficult to establish whether these histologic findings correlate with response to treatment and/or relapse. Our patient’s case is extremely rare given the lack of systemic and serologic features of the disease on top of a complex renal histology. It is uncertain whether his history of HIV contributes to this atypical presentation as both conditions are T cell mediated. Lack of signs of HIV nephropathy on his biopsy make IgG4 the most likely etiology.